High Precision for Hard Processes (HP2 2026)

Session

Track 1 - Amplitudes (process-specific)

T1

Oct 8, 2026, 11:15 AM

NTI Hörsaal, building 30.10 (KIT)

Conveners

Track 1 - Amplitudes (process-specific): Parallel Session V

• Bakar Chargeishvili

Track 1 - Amplitudes (process-specific): Parallel Session VI

• Simone Zoia

62. On non-factorizable corrections to vector boson fusion Higgs production

Linus Götzfried (Universität Regensburg)

10/8/26, 11:15 AM

1

In this talk, I discuss non-factorizable loop contributions entering the NNLO QCD prediction for Higgs boson production via vector boson fusion at the LHC. Firstly, I present a calculation of the one-loop amplitude to higher orders in the dimensional regulator $\varepsilon$, which is required for infrared subtraction terms. Secondly, for two of the relevant two-loop five-point Feynman integral...

23. Analytic two-loop amplitudes for $t\bar{t}j$ production at lepton colliders

Ming-Ming Long (INFN-LNF)

10/8/26, 11:40 AM

1

In this talk, I will present an analytic calculation of the two-loop amplitudes for $e^+e^- \to t\bar{t}j$ at leading-colour approximation. The amplitudes are decomposed into linear combinations of independent tensor structures and scalar form factors. The relevant Feynman integrals are computed analytically via the method of differential equation. After transforming the differential equations...

45. Non-factorisable electroweak corrections at two-loop order

Fazila Ahmadova (University of Zurich)

10/8/26, 12:05 PM

2

In view of the high-precision physics programmes of current and future collider experiments, accurate theoretical predictions for processes involving heavy unstable particles, such as the W and Z bosons or the top quark, are essential. Achieving the required level of precision demands the evaluation of two-loop corrections to the corresponding high-multiplicity and multi-scale amplitudes,...

58. Towards NNLO QED corrections to radiative return processes

Mr Thomas Dave (University of Liverpool), Mr Pau Petit Rosas (University of Liverpool), William Torres Bobadilla (Universidad de Salamanca)

10/8/26, 12:30 PM

1

We present the analytic calculation of the two-loop QED corrections to the process $e^+e^-\to\gamma\gamma^*\to \pi^+\pi^- (\mu^+\mu^-)$, focusing on the initial-state radiation contribution, where the energetic photon is emitted from the leptonic line. The calculation is performed retaining the full dependence on all kinematic invariants, without resorting to small-mass approximations. This...

34. Two-loop QCD corrections for Higgs plus two-jet production through gluon fusion

Viktor Kuschke (PSI, UZH)

10/8/26, 4:15 PM

1

We present two-loop scattering amplitudes in QCD for the hadronic production of a Higgs boson in association with two jets mediated by the top-quark Yukawa coupling.
Our results cover the dominant contributions for all partonic channels, which are computed in the heavy top-mass limit in the leading-color approximation.
We obtained analytic expressions of the amplitudes decomposed in an...

71. Analytic form of the elliptic master integrals for gg->hg at two loops

Bakul Agarwal (University of Edinburgh)

10/8/26, 4:40 PM

1

We present our analytic calculation of the master integrals for gg->gh at 2-loops with internal top quarks, considering the planar elliptic family. We bring the system of differential equations into the epsilon-factorised form using transformations involving elliptic integrals. We present our approach to find a suitable variable change from the kinematic space to the punctured torus. Using...

44. NLO corrections to inclusive $\bar{B} \to X_s \gamma$ decays at subleading power

Riccardo Bartocci (KIT (Karlsruhe Institute of Technology))

10/8/26, 5:05 PM

Theoretical predictions in hadron physics are often limited by non-perturbative uncertainties in QCD. Nevertheless, several phenomenologically important processes require improved theoretical control. Effective field theories, such as Soft-Collinear Effective Theory (SCET) and Heavy Quark Effective Theory (HQET), provide powerful tools to overcome these limitations by exploiting...

36. FeynGraph - A Modern High-Performance Feynman Diagram Toolkit

Jens Braun (Institute for Theoretical Physics (ITP))

10/8/26, 5:30 PM

1

We present FeynGraph, a modern high-performance Feynman diagram generation toolkit designed to integrate seamlessly with modern computational workflows for calculating scattering amplitudes. FeynGraph is designed as a high-performance Rust library with easy-to-use Python bindings, allowing it to be readily used in other tools. With additional features like custom diagram selection filters,...

80. Two-Loop Electroweak Renormalization in the Standard Model and NNLO Corrections to $H\to b\bar{b}$

Zhe Li (Shandong University)

10/8/26, 5:55 PM

Next-generation high-energy colliders, including the HL-LHC, and proposed Higgs factories such as FCC-ee, ILC, and CEPC, aim to probe selected Higgs and electroweak observables at the per-mille level. Achieving the required theoretical precision demands NNLO electroweak predictions alongside high-order QCD corrections. However, complete NNLO EW calculations in the SM remain scarce, with a key...

10. Top Quark Pair Production and Decay: The 1-Higgs-Singlet Model and Pseudoscalar Decay

Vishakha Lingadahally (Royal Holloway, University of London)

The process of top quark pair production through the decay of the scalars in the 1 Higgs Singlet extension of the Standard Model is associated with large interference effects between the loop-induced 'SM-like' Higgs and the heavy Higgs amplitudes, and the QCD continuum background. We attach leptonic decays to the di-top final state at NLO and study the effects of spin correlation in the...